Azbil Corporation

Azbill Corporation

Takuya Ishihara

Masashi Sekine

Masaru Soeda

Hidenobu Tochigi

Hidefumi Harada

Yasuhide Yoshikawa

Yusuke Niimura

Nobuo Sashinami

A pressure sensor includes a diaphragm of a thin plate shape, the diaphragm forming part of a wall surface of a pressure chamber into and out from which a measurement target fluid flows. Multiple recesses are formed in the diaphragm on a side in contact with the measurement target fluid, and an interval between adjacent two of the multiple recesses is 10 &#x3bc;m or less.

Capacitive diaphragm vacuum gauge including a pressure sensor with multiple recesses being formed in the diaphragm

A pressure sensor includes a movable electrode formed in a movable region of a diaphragm, and a fixed electrode formed opposite to the movable electrode. A pressure receiving surface of the diaphragm is held in an inactive state. The inactive pressure receiving surface of the diaphragm is in a state in which molecules of gas to be measured are hard to absorb onto the pressure receiving surface. The pressure receiving surface of the diaphragm can be made inactive by predetermined surface treatment. A layer for making the pressure receiving surface of the diaphragm inactive is formed by the surface treatment, and the pressure receiving surface of the diaphragm is held inactive with the presence of the layer.

Pressure sensor having a surface of a diaphragm held in a chemically inactive state

An electrode pair that forms a pressure-sensitive capacitance Cx in the central portion of a diaphragm is called a first electrode pair (pressure-sensing electrode pair), and another electrode pair that forms a reference capacitance Cr in the circumferential portion of the diaphragm is called a second electrode pair (reference electrode pair). The ratio &#x394;Cx/&#x394;Cr of a change &#x394;Cx in the pressure-sensitive capacitance Cx, which is obtained from the pressure-sensing electrode pair at the time of evacuation, to a change &#x394;Cr in the reference capacitance Cr, which is obtained from the reference electrode pair at the time of evacuation, is calculated as an index for malfunction detection &#x3b1;. Then, the index for malfunction detection &#x3b1; thus calculated is compared with the reference value &#x3b1;ref, which represents the index observed during normal operation, and whether deformation due to a cause other than pressure has been generated in the diaphragm is determined.

Method and device for detecting malfunction of electrostatic-capacitance pressure sensor

Aiming to more easily perform calibration of a sensor output from a pressure sensor, the calibration being necessitated due to the occurrence of sedimentation, a resonance point measurement unit () measures a resonance point of a diaphragm () on the basis of the result obtained by performing measurement of a constant pressure using the pressure sensor while a power supply frequency is changed, a characteristic calculation unit () calculates, on the basis of the measured resonance point, an elastic modulus of the diaphragm () at the time of the measurement of the resonance point, and a correction unit () calculates a corrected sensor sensitivity resulting from correcting a sensor sensitivity of a sensor chip () on the basis of the elastic modulus calculated by the characteristic calculation unit ().

Pressure sensor

A pressure introducing chamber is provided with a baffle plate which is positioned with one surface thereof facing in a direction orthogonal to a direction of travel of a measured medium introduced through a pressure introducing hole into the pressure introducing chamber. A first distance between a pressure receiving surface of a sensor diaphragm and an inner surface of the pressure introducing chamber facing the pressure receiving surface and a second distance between the pressure receiving surface of the sensor diaphragm and the other surface of the baffle plate facing the pressure receiving surface are both smaller than a mean free path of the measured medium in the entire region of the pressure receiving surface of the sensor diaphragm.

Capacitive pressure sensor

A base plate has pressure introducing holes at positions facing a diaphragm support portion. A thickness portion (thick portion) of the diaphragm support portion and a sensor base joined to the diaphragm support portion thus serves as a heat dissipating or absorbing portion and hinders the transfer of thermal energy of a measured medium to a sensor diaphragm.

A temperature difference calculation unit determines a temperature difference between a temperature measured by a first temperature measurement mechanism and a temperature measured by a second temperature measurement mechanism. The first temperature measurement mechanism is disposed on an outer wall surface of an inner container at a position corresponding to an element-arrangement-side space in the inner container. The second temperature measurement mechanism is disposed on an outer peripheral surface of a heater. The heater is disposed outside an outer container that accommodates the inner container and positioned on a wall surface of the outer container.

Pressure sensor having a temperature control unit and a temperature difference calculation unit

A state determination unit compares an output value obtained by a measuring unit with a reference characteristic value that serves as a reference, counts the number of times an excessive pressure application state occurs in which the output value is determined to be equal to or larger than the reference characteristic value, and determines whether the number of times reaches an upper limit that is set. An alarm output unit outputs an alarm when the state determination unit determines that the number of times the output value is equal to or larger than the reference characteristic value reaches the set upper limit.

Vacuum gauge state detection method and system

A pressure change measuring unit causes a temperature control unit to operate and vary the temperature of a sensor chip in a predetermined temperature range, and measures changes in pressure value output from the sensor chip whose temperature is being varied. A temperature characteristic calculating unit calculates a temperature characteristic of the sensor chip from changes in the temperature of the sensor chip caused by the operation of the temperature control unit and changes in pressure value measured by the pressure change measuring unit.

The state of sediment can be estimated based on an initial power supply frequency at which a diaphragm resonates in an initial state in which sediment is not accumulated and a power supply frequency at which the diaphragm resonates after the sediment is accumulated, the state of the sediment can be estimated even in a stage in which the sediment is slightly accumulated on the diaphragm and a zero-point shift does not occur.

Sediment state estimating apparatus, sediment state estimating method, and sediment state estimating system

An electrostatic pressure sensor has a supporting diaphragm bonded to be held between first and second pedestal plates, a sensor chip supported on a top face of a center portion of the second pedestal plate. The supporting diaphragm has in the center portion thereof a large-diameter hole that forms a slit-shaped space between the first and second pedestal plates. The first pedestal plate has at least one inlet hole, for the fluid being measured, connecting to the slit-shaped space. The second pedestal plate has at least an outlet hole, connecting to the slit-shaped space, for directing the fluid being measured to the pressure-sensitive diaphragm of the sensor chip. The pedestal plate has an inlet hole of the first pedestal plate and an outlet hole of the second pedestal plate do not overlap each other in the direction of thickness of the first and second pedestal plates.

Electrostatic pressure sensor

A pressure sensor device has a sensor detecting pressure of a gas that is introduced from the outside, a heater for heating the sensor, a package containing the sensor and the heater, a circuit portion producing an output signal that represents the pressure of the gas based on the detection output detected by the sensor, and a circuit containing portion containing the circuit portion. The package and the circuit containing portion are structured from separate cases and are disposed separately with a connecting structural member interposed therebetween. The connecting structural memberincludes electrode lead pins connecting between the sensor within the package and the circuit portion within the circuit containing portion, insulated pipes for covering the outer peripheries of the electrode lead pins, and coil springs covering the outer peripheries of the insulated pipes.

Pressure sensor device

In an electrostatic capacitance pressure sensor provided with a pressure sensor chip of a diaphragm structure for detecting an electrostatic capacitance in accordance with a pressure of a medium to be measured, one face of a sensor diaphragm of the pressure sensor is a pressure introduction chamber side wherein the medium to be measured is introduced, and the other face is a capacitor chamber side wherein a capacitor portion is formed, where, in the sensor diaphragm, the rigidity is lower towards a center portion from a peripheral edge portion that is a boundary of diaphragm securing portions on the capacitor chamber side.

Growing community of inventors

Chiyoda-ku, Japan

Takuya Ishihara